Playing around with linked lists in c.

lists.c

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <stdbool.h>

typedef struct node {
  int value;
  struct node * next;
} node;

struct node* make_node(int n);
int append(int n, struct node* list);
int prepend(int n, struct node** head);
int pop(struct node** head);
int insert(int n, int pos, struct node** head);
int push(int n, struct node* head);

void free_list(struct node* list);
void print_list(struct node* head);

int main (void) {
  int error = 0;
  node* head = make_node(0);

  for (int i = 1; i < 2; i++) {
    prepend(i, &head);
  }

  int value = 0;
  print_list(head);

  while (value != INT_MAX)
  {
    value = pop(&head);
    if (value != INT_MAX) {
      printf("%d\n", value);
    }
  }

  return error;
}


struct node* make_node(int n)
{
  struct node* node = NULL;
  node = malloc(sizeof(struct node));

  if (node != NULL) {
    node->value = n;
    node->next = NULL;
    return node;
  }
  return NULL;

}

int append(int n, struct node* head)
{
  node* curr = head;
  node* node = make_node(n);

  if (node == NULL) {
    return 1; 
  }

  while(curr->next != NULL) {
    curr = curr->next;
  }

  curr->next = node;
  return 0;
}

int prepend(int n, struct node** head)
{
  if (head == NULL)
  {
    return INT_MAX;
  }

  node* node = make_node(n);
  if (node ==  NULL) {
    return INT_MAX;
  }

  node->next = (*head)->next;
  (*head)->next = node;
  
  return 0;
}

int insert(int n, int pos, struct node** head)
{
  node* curr = *head;
  node* node = make_node(n);

  if (node == NULL) {
    return 1;
  }

  for (int i = 0; i <= pos; i++) {
    if (i == pos) {
      if (curr->next == NULL) {
        curr->next = node;
      } else {
        node->next = curr->next;
        curr->next = node;
      }
    }
    if (curr->next == NULL) {
      return 2;
    }
  }
  return 0;
}

int pop(struct node** head)
{
  if (*head == NULL) {
    free(*head);
    return INT_MAX;
  }

  int value = (*head)->value;

  node* curr = NULL;
  curr = *head;
  *head = (*head)->next;

  free(curr);

  return value;
}

void free_list(struct node* head)
{
  node* curr = head;
  node* next = NULL;
  do {
    next = curr;
    curr = curr->next;
    free(next);
  } while (curr->next != NULL);
  free(curr);
}

void print_list(struct node* head)
{
  node* curr = head;
  do {
    printf("%d\n", curr->value);
    if (curr->next != NULL) {
      curr = curr->next;
    }
    else {
      break;
    }
  } while (true);
}